Wednesday, September 19, 2012

New 2GW Gas Power Plant in Pembrokeshire

RWE Npower has just opened a new 2000MW CCGT Power Station in Pembrokshire (UK). I mentioned in a recent post that there is an ongoing consultation on a draft energy bill, their is also a great deal of controversy about the role that this bill will grant to gas power. This controversy is driven in significant part by the government's statutory climate change advisers the Committee on Climate Change who have highlighted the conflict between unabated gas and legally binding climate targets.

I was curious to find out the gC02/KWh figure for this new station as i was able to find plenty of claims about it's efficiency but no numbers! The tale just got curiouser and curiouser as i looked at their environmental impact assesment which states in section 5.3.5 that the power station:

"if operated at full capacity throughout the year, would emit approximately 5.8 million tones of co2".

Their are 8760 hours per year and the power plant produces 2000MW so at full capacity the power station would produce 17520GWh of electricity whilst emitting 5.8 million tones of co2. This works out at 302g/KWh. This seems very good. However, in an Imperial College ICEPT Discussion Paper by Dr Robert Gross the following is to be found on p9:

"Currently the best achievable performance in a new CCGT would be around 56% efficient, implying around 360g/KWh, neglecting losses. Emissions as low as 300 g/KWh would require efficiency of 66%, well beyond what many believe to be the limits of current designs"

Some doubt is therefore cast upon this figure. The EIA doesn't provide a figure for the co2/kwh that this power plant is capable of. It does invite you to work this out yourself but if you do this and you interpret "operate at full capacity" to mean 24/7 operation you are apparently mislead. Some downtime may be assumed for maintenance but this is not stated.

Furthermore, the actual emissions per KWh will depend on the operating regime about which we are told nothing.

It is also notable that the gas used in LNG, imported at -140 degrees celsius and warmed up by aplication of sifnificant quantities of energy. This is dissapointing as some of this energy could have been used for district heating.

As a final thought, i find it interesting that the proposed Energy Performance Standard currently being considered is 450gC02/KWh. Considering the best technology might enable 300g/KWh: this is quite a gap.